Control of gases through boilers



July 17, 1928. 1,677,749

' J. B. CRANE CONTROL OF GASES THROUGH BOILERS Fild Oct. 24, 1925 4 sheets-sh et 1 WITNESSES July 17, 1928. 1,677,749

J. B. CRANE CONTROL OF GASES THROUGH BOILERS Filed Oct. 24, 1923 4 Sheets-Sheet 2 F! E .2.

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July 17, 1928; \1 ,677,(49

' J. B. CRANE CONTROL OF GASES THROUGH BOILERS Filed, Oct-24. 192 3, 1 [Sheets-Shae; 3

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WITNESSES I k July 17; 1928.

J. B. CRANE CONTROL OF GASE$ THRQUGH 501L311;

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Patented July 17, 1928.

UNITED STATES PATENT OFFICE.

JOSEPH B. CRANE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO INTERNATIONAL COMBUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

Application filed October 24,- 1923. Serial No. 670,490.

Although a considerable percentage of heat generated in the furnace of a boiler is transmitted to the heating surface by radiation from the hot surfaces of the furnace and the fuel bed, the efliciency of a boiler depends principally on the heat imparted to the heating surfaces by convection, i. e., the contact of hot gaseous particles of gas with the heating surfaces, and the greater the number of such'particles in astream of gas caused to contact with the heating surface in a unit, the higher the efliciency attained. Hence, a high velocity or rate of flow is desirable. With a given rate of flow it is evident that the number of hot particles of gas brought into contact with a heating surface will be dependent on the length of such surfaces and also the cross section of each elementary stream of gas traversing the heating surfaces. It is known that in streams of hot gases passing along a; heat absorbing surface, there will be a diffusive action, i. e., a movement of the hot particles to and from the absorbing surfaces. The length of a portion of a furnace and this back and forth movement of the hot particles is dependent on the cross section or mean hydraulic depth of the streams of gas, and hence the smaller this cross sec- 4 tion or mean hydraulic depth the greater the proportion of hot particles of gas which will contact with the heat absorbing surfaces.

In the manufacture of water tube boilers, the ends of the tubes are secured in holes formed in the drums or headers and these holes must be spaced such distances apart as not detrimentally to weaken the drums or headers as against internal pressures. This 40 necessary spacing of the tubes permits of the passage of streams of hot gases of such large cross section or hydraulic mean depth that a very large percentage of the .hot articles will either not contact with the surfaces of the tubes at all or so infrequently in passing through the boiler that the gases entering the stack will have a very high temperature. In Fig. 1 I have illustrated my invention in connection with a vertical water tube boiler and have shown a fragmentary portion of the combustion chamber and boiler setting in order to indicate the relation of the boiler to different parts of the furnace.

face of a boiler and also the frequency of.

The combustion chamber A of any well known form has the grate 8 in the lower part thereof, and the lower drum 9 of the boiler is adjacent the bridge wall 10. The rear wall of the furnace is indicated fragmentarilyat 11, the side wall at 12, and the oiftake for the products of combustion is shown at 13. The gaseous products of-com bustion will flow from the combustion chamber A through the bank of tubes of the boiler and out through the ofl'take in a well known manner- The quantity of heat imparted to a boiler by radiation from the hot surfaces of the furnace and the fuel bed is dependent on the difference between the fourth power of 7 the absolute temperature of the hot and cold surfaces, but under the present practice only a comparatively small proportion of the heating surfaces of a boiler, i. e., those immediately adjacent to the combustion chamber, are acted on by the radiant heat, as the hot gases radiate little heat. 7

The invention described herein has for its object the provision of means whereby the cross sect-ion or the hydraulic mean depth is so reduced that the diffusive action of astream of hot gases may be effective to increase thepercentage of hot particles of gas brought into contact with the heating surcontact of the particles with such surfaces. It is a further object of the invention to subject practically all of the tubes to radiant heat. The invention is hereinafter more fully described and claimed.

In the accompanying drawing forming a part of this specification, Fig. 1 is 'a sectional elevation of a vertical watetr tube boiler embodying the improvement claimed herein: Fig. 2 is a detail elevation showing two tubes and an interposed wall or partition; Fig. 3 is a sectional elevation on a plane indicated by the line III-III, Fig. 1: Fig. 4 is a sectional view on a; plane indicated by the line IVIV, Fig. 2; Fig. 5 is a sectional plan view on an enlarged scale, the plane of section being indicated by the line V+-V, Fig. 1; Fig. 6 is asectional view on a vertical plane across the tubes of a horizontal water tube boiler showing the 106 arrangement of the wall or partition when the tubes are arranged in staggered relation; and Fig. 7 is a similar view showing ment.

In the practice of the invention walls or partitions 1 formed of refractory material such as asbestos board, are arranged between adjacent tubes or rows and in the case of boilers having upper and lower drums and connecting tubes or banks of tubes, the walls or partitions extend vertically from drum to drum. In order that these partitions may not shield the tubes adjacent to the fuel bed .from the radiant heat from the fuel bed and the walls of the combustion chamber or, furnace these partitions will extend horizontally from the third or fourth front row of tubes backward for theentire depth of the boiler. These walls or partitions are made of a thickness less than the spaces between adjacent tubes or adjacent lines of tubes proportional to the desired thickness of the streams of hot gases flowing from the, combustion chamber and are spaced equal distances from adjacent tubes. These walls can be conveniently formed in horizontal sections and held in alinement and away from the tubes by blocks 2 having grooved faces to fit around the tubes and connected by webs 3 intermediate the ends of the blocks; As shown in 'Fig. 4 these H-shaped pieces engage the edges of adjacent sections of the walls and also bear on adjacent tubes.

In order to prevent a short circuiting of the gases, whereby the upper portions of the tubes will not be efliciently heated. the walls or partitions are made tapering from their lower ends, as shown in Fig. 4, so that the vertical spaces between adjacent walls or partitions will be progressively larger from the lower portions of the tubes upward, thus ensuring an equal or approximately equal flow of gases towards the stack: at all points between the drums.

As shown in Figs. 6 and], the improve ment claimed herein may be embodied in boilers having their water tubes arranged horizontally or approximately so. In some types of this class of boilers, the tubes are arranged in staggered relation vertically, as shown in Fig. 8, in which' case the, wallsor partitions would be arranged at an angle to the side walls 7 of the boiler setting, as shown, and hence if the partition were extended so that an end wouldabut against a side wall or walls, it would prevent hot gases from access to tubes above or below such partition. As for example, if the partition 1 should be extended further down-5 wards, it would pervent hot gases from flowing. to and around tubes above and to the left of said partition. Similarly, if the par titions 1 should be extended upwards to the side wall of the setting, there would not be any circulation of gases'entering the bank of tubes below and at the right of partition 1". Such gases would be simply pocketed. In order to ensure the flow of gases around all of the tubes, those partitions which if extended so that their ends would contact with a side wall or come into such proximity thereto as to prevent ample flow to and around tubes adjacent to the side walls of the setting," are stoppedoflf as shown in Fig.8.

When, however, the tubes are arranged in alinement vertically, as shown in Fig. 7, the partitions would be arranged vertically between adjacent rows of the tubes.

It will be readily understood by those skilled in the art that as the streams of gas can be made very thin or small in cross section, the percentage of hot particles of gas. brought into contact with the tubes by the diffusive action in the streams will be very large. And vfurther, these walls'or partitions will be brought to or approximately to the temperature of the gases, and the tubes will be heated by heat radiated .from the surfaces of the walls or partitions.

The walls or partitions may be so constructed that ad acent walls form passages enclosing a plurality of tubes so that the gases flowing between such adjacent walls are confinedlaterally and flow in substantial unbroken sheets along opposite sides of the enclosed rows of tubes.

I claim herein as my invention:

1. A water tube boiler consisting of a bank of tubes arranged inparallel rows, a combustion chamber and an outlet for products of combustion, said elements being so arranged that the gases will flow in a direction at an angle to the tubes in combination with a plurality of substantially continuous walls or partitions extendingv between and substantially parallel with adjacent parallel rows of tubes in a direction of the flow of the gases and spaced from the tubes forming the rows, said walls or partitions being substantially continuous through the bank and adapted to divide the gases flowing from the combustion chamber into a plurality of streams laterally confined to operate on a plurality of tubes forming the rows or lines between adjacent walls.

'2. A water tube boiler consisting of upper and lower drums and a bank of tubes arranged in parallel rows connecting said drums in combination with substantially continuous vertical walls or partitions arranged between and substantially parallel with the rows of tubes and spaced from the tubes forming the rows and extending from the lower to the upper drum.

3. water tube boiler consisting of upper and lower drums and tubes connecting said drums in combination with vertical walls or partitions arranged between and substantially parallel with the rows of tubes and spaced fromthe tubes forming the rows and extending from the lower to the upper drum 30 having a and tapering from their lower ends upwards.

t. In' combination, a furnace having. a combustion chamber andan outlet for the products of combustion, a water tube boiler bank of tubes between the chamber and the outlet, substantially continuous partitions between rows of parallel tubes and spaced from the tubes of the rows, the partitions forming passages in said bank extending substantially in the direction of flow of the gaseous products of combustion.

5. In combination, a vfurnace having a combustion chamber, a vertical water tube boiler to the rear of the combustion chain- 15 I her, the tubes of which are arran m transverse arallel rows and an out et beyond the hoiler, substantially continuous partitions extending between and longitudinally of the rows of tubes and forming substantially of the bank of, tubes whereby gases flow through the bank in a direction transverse thereof.

my hand.

JOSEPH B. CRANE.

continuous passages transversely- In testimony whereof, I have hereunto set 25 

